RANCANG BANGUN ALAT PASTEURISASI NON THERMAL DENGAN PULSED ELECTRIC FIELD (PEF)

ABSTRACTPackaged beverages have become a product that is very much on the market both internationally and nationally. In the process of making packaged beverages, in order to last longer the microbes in the drink must first be inactivated in order for the drink to last longer, the microbial inactivation process in the drink is called pasteurization. Convernsional pasteurization is done by heating the drink to be in production. But the high temperature of the drink can change the taste, color, and even nutrition of the drink. This is underpinning the non-thermal pasteurization process by using high voltage impulses (Pulsed Electric Field,PEF). PEF is a technology that utilizes high voltage DC to produce a field between two electrodes. Pateurization occurs when between electrodes there is milk that is flowed with high voltage DC. High voltage generation is performed using flyback transformers with voltage output up to 30 kV. In the pasteurization process given 6 voltage variations namely 5, 10, 12,5, 15, 20, and 30 kV. Pasteurization results are then tested in fmipa microbiology laboratory to find out the success of the tools that have been made. In each voltage variation it is obtained that all treatments have reached pasteurized milk quality standards based on SNI where at 5kV voltage variation can inactivat microbes up to 83.33%, voltage variation of 10kV can inactivat microbes up to 94.5%, At a voltage variation of 12.5 kV can inactivae microbes up to 83.6%, 15kV voltage variation can inactivae microbes up to 88.8%, while voltage variation of 20 kV can inactivae microbes up to 84.2% and at voltage variation 30 kV can inactivae microbes up to 84.8%.Key Words: PEF, Flyback Transformer, ZVS Driver, Pasteurization.

Effect of temperature and duration of thermal pasteurization on polyphenol oxidase (PPO) enzyme activity, total plate count (TPC), physicochemical and organoleptic properties of Cavendish banana fruit juice (Musa cavendishii)

This research aims to determine the effect of temperature and duration of thermal pasteurization process in Cavendish banana juice. Cavendish banana is an abundant cultivated banana that has not been used properly, which is a climacteric fruit that has increased ethylene production after harvesting. Cavendish bananas have great potential as fruit juice. Pasteurization was carried out at temperatures of 55, 60, 65, 70 and 75 ℃ for 5, 10, and 15 minutes. Pasteurization with higher temperature and time can increase the total dissolved sugar and viscosity as well as decrease the pH value and PPO enzyme activity. The reducing sugar content of Cavendish banana juice was determined using the DNSA method with the greatest value at 55 ℃ for 5 minutes, which is 9.53%. Meanwhile, the content of phenol and flavonoid was determined using the Krishnan and Sinija method. The highest value of phenol and flavonoid content at 60 ℃ for 5 minutes, was 0.1728 mg GAE/g and 0.1583 mg QE/g sample. Antioxidant activity was determined using the DPPH method and the greatest percentage of inhibition at 60 ℃ for 5 minutes, which is 61.60%. Vitamin C levels were identified by the UV-Vis spectrophotometry method with the greatest value at 55 ℃ for 5 minutes, which is 1.1409 mg /100 g. The Total Plate Count (TPC) of Cavendish banana juice decreased after pasteurization with the smallest total number of bacteria at 75 ℃ for 15 minutes, with a value of 3.2×101 CFU/ml. Pasteurization process at 75 ℃ for 15 minutes can reduce the activity of PPO enzyme as much as 97%. In the organoleptic test, preferred level of Cavendish banana juice to all attributes of the average hedonic scale with the category of the likes.

Perbedaan nilai gizi susu sapi setelah pasteurisasi non termal dengan HPEF (High Pulsed Electric Field)

Cow's milk is the secretion of a cow that has perfect nutritional value but is easily damaged. Efforts to extend the shelf life of milk, milk is usually stored in a box freezer or by thermal pasteurization. However, this thermal processing can change the smell, taste, colour and reduce the nutritional content of milk, especially protein, which is a heat resistant substance. Alternative non-thermal technology that HPEF can apply. The method of this research was descriptive, describing the nutritional value of milk before and after had been HPEF Implementation. After non-thermal pasteurized cow's milk with HPEF, the nutritional value of cow's milk was better than fresh cow's milk. In unprocessed milk with HPEF, the fat content decreased by 3,77%. Protein content increased 0,15%, lactose 0,29%, and increased mineral content 0,05%. The TPC test on milk showed 6,91 x 102 cfu/ml. HPEF implementation can effectively reduce fat levels, increase protein, lactose levels, and increase mineral levels in milk. Non-thermal pasteurized cow's milk with HPEF can be immediately ready for consumption

Microbial analysis and virulence genes detection of milk preserved using heat-assisted pulsed electric field

Objective Microbial analysis in milk preserved using heat-assisted Pulsed Electric Field (PEF) need to be assessed. In this study we analyze the microbial quality and virulence-associated genes in milk samples preserved using heat-assisted PEF from several producers in Indonesia. Results Milk samples were collected consisting of raw milk, milks taken after the heating, PEF, mixing, cooling, and packaging. Microbiological and Polymerase Chain Reaction (PCR) detection for virulence genes were performed. Heat-assisted PEF treatment gave 2.7–7.47 log reduction for TPC; 1.6–2.56 log reduction for MPN number; 3.13–6.48 log reduction for S. aureus; and for B. cereus there was an increase of 0.76 log and a reduction of 0.46 log. While milk samples from thermal pasteurization gave log reduction numbers of TPC, MPN, and S. aureus respectively 5.28; 2.56; and 4.73, for B. cereus was increasing 2.4 log. Producer C performed the best results with significant reduction compared with others (p < 0.005). There were no colonies of L. monocytogenes found in all of the samples. PCR results showed that milk samples possessed virulence genes 17.5% (10/57) of invA genes, 54.4% (31/57) of nheA genes, 68.4% (39/57) of cytK genes, 38.6% (22/57) of nuc genes, 63.2% (36/57) of ileS genes, while hly and actA genes were not detected.

High Hydrostatic Pressure vs. Thermal Pasteurization: The Effect on the Bioactive Compound Profile of a Citrus Maqui Beverage

The effects of high hydrostatic pressure (HHP) compared to thermal pasteurization (TP) were studied in healthy citrus-maqui beverages. The impact of the processing technologies on the microbiological and phytochemical profile was assessed by applying two HHP treatments at 450 and 600 MPa for 180 s and TP at 85 °C for 15 s. The shelf life under refrigeration (4 °C) and room temperature (20 °C) was monitored for 90 days. All treatments ensured microbiological stability at both storage temperatures. Aside from that, the physicochemical parameters were not significantly different after processing or throughout the storage period. Regarding color parameters, an increase in the reddish coloration was observed during storage for those beverages treated by HHP. In general, phenolic compounds were little affected by the processing technique, even when treatment under HHP was more stable than by TP during storage. On the other hand, vitamin C showed great degradation after processing under any condition. It can be concluded that HHP is an effective alternative to thermal treatments, achieving effective microbial inactivation and extending the shelf life of the juices by contributing to a better preservation of color and bioactive compounds.